Last updated on April 28, 2022
What Is a Hypervisor and What Are Its Benefits? | Parallels Explains
In simple terms, a hypervisor definition would be a software layer that creates and runs many isolated virtual machines (VMs) over single hardware. Before dwelling on the details of what a hypervisor is, it makes sense to understand the technology that is tied to it – virtualization.
Virtualization is essentially the creation of a virtual form of a resource (server, desktop, operating system, storage space, network, or files). The virtualization process partitions the underlying hardware so that each partition runs as a separate, isolated virtual machine. This is where the hypervisor steps into the equation.
It can also be thought of as the operating system for virtualized systems. It is software that partitions, abstracts, and isolates OS and applications from the underlying computer hardware.
What are the Features of a Hypervisor?
There are two major features of hypervisors:
Partitioning
Hypervisors partition the underlying hardware. Partitioning is a method for efficiently using an abundance of hardware resources by enabling multiple independent software payloads to run concurrently on the same hardware. A partition is a logical unit of isolation, supported by the hypervisor, in which operating systems execute. The virtualization management stack runs in the parent partition and has direct access to hardware devices. The root partition then creates the child partitions which host the guest operating systems.
Resource Distribution
Hypervisors manage independent virtual machines by distributing resources like memory, network bandwidth, etc. among them. Maintaining a healthy balance of virtual machine resources will optimize individual VM capabilities, thereby improving your overall network performance.
Resource allocation describes the process of figuring out the best way to distribute limited resources between multiple applications. Virtual machine resource allocation is this same task: determining how to best divide VM resources between the VMs present in your network. Effective resource allocation will ensure all VMs complete jobs successfully and without draining excessive resources.
Virtual Machine Management
Upon the request of the user, hypervisors can start/stop independent virtual machines.
Isolation
Hypervisors ensure that the virtual machines are isolated from each other. This helps ensure that a problem in one virtual machine does not affect the other.
Communication
The hypervisor also handles the communication amongst virtual machines over virtual networks, enabling VMs to connect with one other.
How Does a Hypervisor Work?
- They operate on the server level and can be either physical or virtual, and hardware or software-defined
- They load the client operating systems of the VMs
- It distributes the computing resources such as CPU, memory, bandwidth, and disk storage for each of the VMs. It does this by creating pools of hardware resources, which it then allocates to VMs.
- VMs can create requests for the hypervisor through API calls.
What Types of Hypervisors Are There?
It’s possible to differentiate between two types of hypervisors: Type 1 (bare metal) and Type 2 (embedded or hosted).
Type I / Bare-metal / Native Hypervisors
A Type I hypervisor is also called bare-metal or native hypervisor. They run the host machine’s hardware directly, so the hypervisor software is the operating system. In simple terms, the hypervisor has direct hardware access, without any other software interfering.
Type I is the best for enterprise computing and large-scale deployments. The advantages of Type I hypervisors are:
Scalability
The ability to directly assign resources makes Type I scalable.
Optimization of physical resources
Type I allow optimization of single server hardware, thus freeing up data costs and cutting down energy usage.
Better Resource Allocation
Type I hypervisors give administrators the ability to set resource allocation manually. Resource management is a dynamic and customized option in Type I.
Type 2 / Embedded / Hosted Hypervisors
A Type 2 hypervisor is also called an embedded or hosted hypervisor. These are built on top of the operating system and rely on the host machine’s underlying operating system.
Also referred to as the hosted hypervisor, it runs as an application within the operating system, which in turn runs directly on the host computer. Type II hypervisors also support multiple guest machines but are not allowed to directly access the host hardware and its resources. The pre-existing operating system manages the memory, network, and storage allocation, creating a certain amount of latency and restrictions. In addition, if the OS crashes, the hypervisor will also crash, and possible data loss might occur.
The advantages of Type 2 hypervisors are:
Easier setup
These hypervisors are easier to set up and manage as there is an underlying operating system to work with.
Easier management
Type 2 hypervisors do not require a dedicated administrator.
Compatibility
Type 2 hypervisors are compatible with a wider range of hardware, since they run on top of an OS, instead of specific hardware machines.
KVM hypervisor
KVM (Kernel-based Virtual Machine) is a mix of Type I and Type 2 hypervisors. It is built into Linux, and it turns Linux into a Type I hypervisor. This type of hypervisor:
- Is secure
- Gives plenty of storage capabilities
- Has adequate hardware support and memory management capabilities
- Offers low latency
- Allows for greater prioritization of apps
- Offers better scalability, scheduling, and resource control
Differences between a Hypervisor and a Container
At higher levels, a hypervisor and a container provide similar functionalities. They both provide an isolated and packaged environment containing various IT components. However, each is different in how it handles scalability and portability. A hypervisor abstracts the underlying hardware from the host’s operating system and apps and is the core technology behind virtualization.
A hypervisor allows a physical server to operate multiple VMs as guests run alongside each other. Each VM can run a different OS. A hypervisor allocates each VM resource such as CPU, memory, storage, and network to run the guest OS and applications. Since each VM contains the virtualized hardware, guest OS, and installed applications, a hypervisor consumes more computing resources.
In contrast, a container through a containerization engine packages an application together with its binaries and other dependencies into a single unit. Once packaged, you can run containers on any platform provided you’ve installed a corresponding container engine. This way, a container engine performs the same function that a hypervisor does for VMs.
While a hypervisor abstracts the hardware resources for multiple VMs to run their own OSs, a container engine abstracts the OS to allow containers to run multiple applications. Since containers share the same OS kernel, containers are lightweight, boot quickly, and maximize the server resources utilization.
Benefits of Using Hypervisors
Data Replication
Cloning and replicating virtual machines is difficult. Storage-based replication methods require replicating the entire volume of all the virtual machines in your server. If there are a lot of virtual machines in your server then replicating the entire volume requires massive amounts of storage space.
Hypervisors can be used for easy cloning and replication. Hypervisor-based replication is easier and more cost-effective than any other replication method of virtual machines.
With hypervisor-based replication you can simply choose the VMs and the parts that are to be replicated, saving up on storage space. Hypervisor-based replication is also hardware neutral, meaning that you can store any data duplicates to any storage device with ease.
Consolidating Servers
Hypervisors also offer inbuilt graphical dashboards. You can also download additional enhancements to the inbuilt dashboards for better visibility. This ability lets you consolidate and manage your servers centrally even when they are running different operating systems.
Portability
Hypervisors allow multiple operating systems to reside on the same physical server (host machine). They are portable due to the virtual machines that they run are independent of the physical machine.
Desktop Virtualization
Hypervisors can also be efficiently used for desktop virtualization. You can easily host a virtual desktop on a server, and the desktop replicates the user’s physical desktop. This lets employees access their workstations over the Internet through client devices, allowing them to work remotely.
Which Type of Hypervisor is Best for You?
The hypervisor you choose depends greatly on your needs as an organization, the cost that your organization is ready to bear, and the expertise that you have inside your organization to manage virtual machines.
Small Businesses
On a general basis, it makes sense for small businesses to adopt Type II hypervisors.
Type II have lower costs, are easier to set up, and do not require a dedicated administrator to manage them. They work well for small organizations where latency is not an issue, and when the number of virtual machines required is comparatively low.
Large Corporations
Large corporations and businesses require many virtual machines for their deployments. In such a case Type I is more suitable.
Type I hypervisors have low latency times, as they can access the hardware directly. They are widely acknowledged as the best performing and most efficient hypervisors that require an administrator to manually set resource allocation based on the application’s priority. They might go higher in terms of costs because of the need to deploy on bare metal. However, they win in terms of security as they isolate virtual machines from each other.
Security Considerations for Hypervisors
Whatever is running inside a VM will not interfere with anything else running on the host hardware because a VM provides an environment that is isolated from the rest of a system. Due to this isolation, should a VM get hacked, the entire system should not be compromised.
However, should the hypervisor itself become compromised, it can cause issues for any of the VMs that the hypervisor would be managing, thus leaving the data within each VM vulnerable.
Parallels RAS: A Cost-Effective Virtualization Solution
Parallels® Remote Application Server (RAS) is a virtualization solution that enables businesses to publish both applications and desktops to any device using a single license. It is complete, easy to deploy, and cost-effective. One of the key features of Parallels RAS is the ability to publish virtual desktop infrastructure (VDI) desktops. These VDI desktops are, in turn, hosted in hypervisors.
One of the best features provided by Parallels RAS when it comes to virtualization is the support for most of the major hypervisors and hyper-converged systems (Microsoft Hyper-V, VMware ESXi, Scale Computing HC3, and Nutanix Acropolis). This flexibility allows businesses to adopt virtualization without having to worry about vendors.
Additionally, Parallels RAS also supports multiple hypervisors under the same infrastructure, allowing existing infrastructures to be managed from the Parallels RAS Console with ease.
The Parallels RAS Console enables administrators to both configure and administer different hypervisors from a central location. Parallels RAS also supports multiple OSs under the same pool of resources, even from different hypervisors. Additionally, it allows IT, administrators, to:
- Group VMs based on the type of hypervisors.
- Deploy servers and VMs.
- Monitor resources.
- Provide assistance.
- Manage connected devices from a single pane of glass.
Reap the benefits of virtualization with Parallels RAS!
